(a) a simple model for a rubber band assumes that the rubber may be represented by polymer chain consisting of n links each of length x. assume that the links are weightless, and there is no interaction energy apart from the weak thermal coupling. the links all lie along the y-axis but they may be oriented in the + y or - y direction the ends of the chain are distance l apart. when the strip of rubber carries a load w, its energy e is related to the number of upward links n by e 2n^w. for an isolated rubber strip with energy e, write an number of states in terms of the numbern of upward links. (i) expression for the [2 marks write down an (11) expression for the entropy s as a function of n [2 marks (b) hence show that the equilibrium temperature t is given by 2 w t = n-n k ln [4 marks] (c) when the same model is used to represent a strip of rubber at constant temperature t, its average number of upward links n is found to be n= e2w/kt +1 compare the rela n and t in parts (a) and (b) s betv comment.